Japanese Patent Application Publication Nos. 2008-230162 and 2008-238792 disclose an ink jet recording device including a cartridge storing therein ink, an attachment portion to which the cartridge is attached and from which the cartridge is detached, a sub-tank storing ink supplied from the cartridge attached to the attachment portion, and a recording portion ejecting ink stored in the sub-tank to form an image on an image recording medium.
The cartridge and the sub-tank are communicated with an atmosphere. Therefore, level of ink stored in the cartridge is equal to that stored in the sub-tank at least during a state where the recording portion does not eject ink, because ink can be moved between the cartridge and the sub-tank due to hydraulic head difference.